METHOD AND DEVICE FOR CHECKING THE QUALITY OF A CRIMPING

Abstract

Disclosed is a method and a device for checking the quality of a crimping of a specified cable with a specified contact sleeve using a sensor system for measuring a force and a displacement of a device for the actuation and/or force application of a crimping unit and using an electronic analysis system. In the method a force/displacement curve is detected during the crimping process and is displayed on a screen, wherein the method has the following steps: a stored reference model is displayed on the screen together with the detected force/displacement curve, said reference model having a first and a second envelope curve which define a tolerance range;—comparing the force/displacement curve with the reference model, thereby ascertaining whether the force/displacement curve lies in the tolerance range; and—arriving at a conclusion regarding the quality of the crimping from the comparison.

Claims

1. A method for creating a reference model for checking the quality of a crimp of a predefined cable with a predefined contact sleeve and with a predefined crimp height using a sensor system for measuring a force and a displacement of an apparatus for the actuation and/or pressure application of a crimping unit and an electronic evaluation system, wherein a force/displacement curve is detected during crimping and displayed on a screen, comprising the steps of: performing a crimp of a cable with a contact sleeve and detecting and displaying a force/displacement curve of the crimp on the screen in a first step; assessing the quality of the crimp via visual inspection by an operator and/or with the use of suitable testing instruments in a second step; using a force/displacement curve of a positively assessed crimp with a predefined quality for a family of force/displacement curves with a predefined number of force/displacement curves in a third step; repeating the first, second and third steps with a further cable with a further contact sleeve, until a predefined number is reached, in a fourth step; defining a tolerance range with a predefined tolerance and/or taking into account the predefined quality and/or the predefined crimp height and/or the predefined cable and/or the predefined contact sleeve and/or the predefined number by specifying a first and second envelope, which delimit the family of the force/displacement curves, in a fifth step; recording the first and second envelope and/or the tolerance range and/or the family of force/displacement curves as a reference model for use in a method for checking the quality of a crimp.

2. The method as claimed in claim 1, wherein, in a sixth step, further data characterizing the reference model and/or a crimp are stored, wherein the data comprise a time stamp and/or a location and/or ID information relating to the crimping device used and/or ID information relating to the operator and/or the predefined number and/or the predefined cable and/or the predefined contact sleeve and/or information relating to the assessment of force/displacement curves of faulty crimps.

3. The method as claimed in claim 1, wherein a performance of the method at least from the first step to the fourth step is added to a number of performances of the method which have already taken place, and/or, in the fifth step, the tolerance range is defined taking into account the number, and/or the further data characterizing the reference model and/or a crimp comprise the number of performances.

4. A method for checking the quality of a crimp of a predefined cable with a predefined contact sleeve and with a predefined crimp height using a sensor system for measuring a force and a displacement of an apparatus for the actuation and/or pressure application of a crimping unit and an electronic evaluation system, wherein a force/displacement curve is detected during crimping and displayed on a screen, comprising the steps of: a stored reference model is displayed on the screen together with the detected force/displacement curve, which reference model has a first and second envelope curve, which delimit a tolerance range; a comparison of the force/displacement curve with the reference model is performed, wherein it is determined whether the force/displacement curve is in the tolerance range; a statement relating to the quality of the crimp is generated from the comparison.

5. The method as claimed in claim 4, wherein the quality of the crimp corresponds to a predefined desirable quality if the force/displacement curve is in the tolerance range.

6. The method as claimed in claim 4, wherein the quality of the crimp is rejected if the force/displacement curve is at least partially outside the tolerance range.

7. The method as claimed in claim 6, wherein a qualitative fault analysis of the crimp is derived from the comparison of the force/displacement curve with the reference model.

8. The method as claimed in claim 1, wherein the force/displacement curves are used for updating the reference model, wherein step five and/or step six is performed, wherein the performance of a crimping process is added to the predefined number and/or the number of performances, and wherein the update is performed in an automated manner and/or at the instigation of an operator.

9. The method as claimed in claim 1, wherein the tolerance range is variable according to the displacement and/or the force.

10. The method as claimed in claim 1 wherein at least one Hall sensor is used for the displacement measurement and/or at least one piezoelectric sensor for the force measurement.

11. A crimping device for checking a quality of a crimp of a predefined cable with a predefined contact sleeve using a sensor system for measuring a force and a displacement of an apparatus for the actuation and/or pressure application of a crimping unit and an electronic evaluation system, wherein a force/displacement curve is detected during crimping and displayed on a screen, said device having the features: the crimping unit is configured for press-connecting the cable to the contact sleeve; the apparatus for the actuation of the crimping unit has a pneumatic pressure apparatus with a cylinder and a piston, which are in operative communication with the crimping unit via a lever; and an adjustment mechanism is provided for setting a predefined crimp height; wherein the crimping device is suitably designed for performing a method as claimed in claim 1.

12. The crimping device as claimed in claim 11, with at least one Hall sensor for the displacement measurement and/or at least one piezoelectric sensor for the force measurement.

13. The crimping device as claimed in claim 11, wherein the crimping unit is an indent crimping unit and preferably a two-mandrel crimping unit and particularly preferably a four-mandrel crimping unit, and wherein the contact sleeve is a turned contact sleeve.

14. The method as claimed in claim 4, wherein a first crimping device and a second identical crimping device are for checking the quality of the crimp, wherein each crimping device comprises a crimping unit is configured for press-connecting the cable to the contact sleeve; wherein the apparatus for the actuation of the crimping unit has a pneumatic pressure apparatus with a cylinder and a piston, which are in operative communication with the crimping unit via a lever; and an adjustment mechanism is provided for setting a predefined crimp height; wherein the crimping device is used for creating the reference model for checking the quality of a crimp of a predefined cable with a predefined contact sleeve and with a predefined crimp height using a sensor system for measuring a force and a displacement of an apparatus for the actuation and/or pressure application of a crimping unit and an electronic evaluation system, wherein a force/displacement curve is detected during crimping and displayed on a screen, said method comprising the steps of: performing a crimp of a cable with a contact sleeve and detecting and displaying a force/displacement curve of the crimp on the screen in a first step; assessing the quality of the crimp via visual inspection by an operator and/or with the use of suitable testing instruments in a second step; using a force/displacement curve of a positively assessed crimp with a predefined quality for a family of force/displacement curves with a predefined number of force/displacement curves in a third step; repeating the first, second and third steps with a further cable with a further contact sleeve, until a predefined number is reached, in a fourth step; defining a tolerance range with a predefined tolerance and/or taking into account the predefined quality and/or the predefined crimp height and/or the predefined cable and/or the predefined contact sleeve and/or the predefined number by specifying a first and second envelope, which delimit the family of the force/displacement curves, in a fifth step; recording the first and second envelope and/or the tolerance range and/or the family of force/displacement curves as a reference model for use in a method for checking the quality of a crimp, wherein a reference model is created using a second crimping device.

15. The method as claimed in claim 14, wherein the reference model is adapted to the characteristics of the first crimping device by updating the reference model wherein routines of a software program provided on the electronic evaluation system are used for performing the method and the method.

Description

EXEMPLARY EMBODIMENTS

[0045] Exemplary embodiments of the invention are illustrated in the drawings and will be explained in more detail below. In the drawings:

[0046] FIG. 1A shows a schematic illustration of a crimping device with a crimping unit according to an embodiment of the invention;

[0047] FIG. 1B shows an enlarged detailed illustration of the crimping unit of FIG. 1A;

[0048] FIG. 1C shows an enlarged mandrel of the crimping unit of FIGS. 1A and 1B,

[0049] FIG. 1D shows a cable with a contact sleeve, separately and crimped to one another;

[0050] FIG. 2A shows a force/displacement curve of a crimp according to an embodiment of the invention;

[0051] FIG. 2B shows a cross-section through a contact sleeve provided as intended for crimping with a cable;

[0052] FIG. 2C-FIG. 2F each show microsections of a cross-section through a crimp of the contact sleeve with the cable of FIG. 2B in various stages of crimping;

[0053] FIG. 3A shows a further enlarged illustration of the crimping unit of FIG. 1A in a rest position, together with a contact sleeve arranged as intended for crimping and a cable;

[0054] FIG. 3B the crimping unit of FIG. 3A in a first position;

[0055] FIG. 3C the crimping unit of FIGS. 3A and 3B in a further position;

[0056] FIG. 4A further force/displacement curves of a crimp together with two envelopes of a reference model according to an embodiment of the invention;

[0057] FIG. 4B a reference model for checking the quality of a crimp according to an embodiment of the invention; and

[0058] FIG. 5 a schematic flow chart of a method for creating a reference model of FIG. 4B.

[0059] The figures contain partially simplified, schematic illustrations. Identical reference signs are sometimes used for elements which are similar but possibly not identical. Different views of similar elements may be drawn to different scales. For the sake of simplicity and clarity, only one similar or similar type of element is denoted by a reference sign in the drawings in each case.

[0060] FIG. 1A shows a schematic illustration of a crimping device 1 according to an embodiment of the invention, and FIG. 1D shows a cable 4 with a contact sleeve 3, mutually separate and crimped to one another. The contact sleeve 3 is a turned contact sleeve 3.

[0061] The crimping device 1 is an indent crimping device and in particular a four-mandrel crimping device with a crimping unit 2 having four mandrels 20, which is particularly suitable for press-connecting a strand of a stripped single-core cable 4 to a turned contact sleeve 3.

[0062] For the actuation of the crimping unit 2, the crimping device 1 has a pneumatic pressure apparatus with a cylinder 10 and a piston 11, which is in operative communication with the crimping unit 2 via a lever 130. A suitable adjustment mechanism 12 is provided for setting a predefined crimp height.

[0063] For a crimp by means of a press-connection of a contact sleeve 3, in particular a turned contact sleeve 3, and a cable 4, the contact sleeve 3, with the strand of the cable 4 located therein, is inserted as intended into the crimping unit 2, and the crimping unit 2 is actuated by means of the pressure apparatus and subjected to pressure. The lever 130 coupled to the crimping unit 2 is pivoted via a vertical movement and a vertically acting force F of the pressure apparatus. In this case, the crimping unit 2 and the lever 130 are designed and arranged in such a way that the mandrels 20 move towards one another from their rest position P0 or are brought into their rest position P0 during a pivotal movement, which will be described below with reference to FIG. 1B. In this case, the tips of the mandrels 20 are each located on concentric circles, which will be described below with reference to FIGS. 3A, 3B and 3C.

[0064] The crimping device 1 is suitably designed for checking the quality of a crimp of a predefined cable 4 with a predefined contact sleeve 3 and, to this end, has a displacement sensor 13 and at least one force sensor 14. The displacement sensor 13 can suitably be a position transmitter with a Hall sensor and can be provided on the cylinder 10 of the pressure apparatus. The force sensor 14 can suitably be a piezoelectric sensor 14 and can be arranged on the lever 130 and/or at it can be at least one piezoelectric sensor provided on an attachment of the cylinder 10. In this case, the piezoelectric sensors each measure a stress or strain during the actuation of the lever 130 or the counter-force of a pressure acting on the piston 11, which counter force acts on the cylinder 10.

[0065] The sensor system 13, 14 is connected to an electronic evaluation system 5 via a signal and/or data link. The electronic evaluation system 5 controls a screen 50 and displays a force/displacement curve G of a crimp, which is detected using the signals of the sensor system 13, 14, together with further information on the screen 50. An example of a force/displacement curve G is described below with reference to FIG. 2A.

[0066] FIG. 1B shows an enlarged, detailed illustration of the crimping unit 2 and FIG. 10 shows an enlarged mandrel 20 of the crimping unit of FIGS. 1A and 1B. For the sake of clarity, the force sensor 14 on the lever 130 is not illustrated in FIG. 1B.

[0067] The crimping unit 2 has a cylindrical guide, in which four mandrels 20 are mounted to be radially movable. The tips of the mandrels 10 are aligned towards one another. The lever 130 is mounted on the cylindrical guide to be axially pivotable or rotatable and has an inner contour which cooperates with heads of the mandrels 20, which project out of the cylindrical guide. During a pivotal movement of the lever 130, the tips of the mandrels 20 are moved towards one another or away from one another in the direction of the axis of the cylindrical guide or the pivot axis of the lever 130. During crimping, a contact sleeve 3 provided with a cable 4 is thus press-connected to the cable 4 via the actuation of the lever 130 on the axis of the cylindrical guide.

[0068] The crimping unit 2 with its mandrels 20 is moreover described below with reference to FIGS. 3A, 3B and 3C.

[0069] A crimping device 1 with the above-described features is suitable for performing a method V and VM described at the outset and below, also with particular reference to FIG. 5.

[0070] FIG. 2A shows a force/displacement curve G of a crimp of a contact sleeve 3 with a cable 4 of FIG. 1D according to an embodiment of the invention, the crimp being performed by means of a crimping device 1 of FIG. 1A.

[0071] During crimping, the mandrels 20 of the crimping unit 2 are brought from their rest position P0 into further positions P1 to P5, wherein the tips of the mandrels 20 are each arranged on concentric circles. In this case, a displacement X and a force F are measured by the sensor system 13, 14 and are illustrated by the force/displacement curve G. Positions P1 to P5 of the mandrels 20 correlate to the positions P1 to P5 in each case and thereby each correspond to a measured displacement X of the sensor 13.

[0072] An enlarged illustration of the crimping unit 2 of FIG. 1A in the rest position P0, together with a contact sleeve 3 arranged as intended for crimping in the crimping unit 2 and a cable 4, is illustrated in FIG. 3A. In this case, the tips of the mandrels 20 of the crimping unit 2 are arranged concentrically with the contact sleeve 3.

[0073] In this case, a displacement of the mandrels 20 from the position P0 to the position P1 takes place under a constant force F. Accordingly, the progression of the force/displacement curve G is also constant in a first region P0-P1 between the position P0 and the position P1 of the mandrels 20. In the position P1, the mandrels 20 of the crimping unit 2 touch the surface of the contact sleeve 3. This position P1 of the mandrels 20 is illustrated schematically in FIG. 3B.

[0074] In comparison to FIG. 3A, FIG. 2B shows an enlarged and more detailed illustration of a cross-section through a contact sleeve 3 provided as intended for crimping with a cable 4. In addition to individual wires 40 of the strand of the cable 4, the interior of the contact sleeve 30 has a void which is not occupied by the individual wires 40 of the strand. The contact sleeve 3 is intact and its state corresponds to that of the contact sleeve 3 of FIGS. 3A and 3B in the region P0-P1 of the crimp with the force/displacement curve G.

[0075] In the further progression of the force/displacement curve G, the force F increases approximately linearly from the position P1 to a position P2 of the mandrels 20, wherein an elastic deformation of the contact sleeve 3 takes place in this region P1-P2. In this case, the individual wires 40 of the strand of the cable 4 are arranged in the contact sleeve 3 together with a comparatively smaller void, which is illustrated in a microsection of the contact sleeve 3 for the region P1-P2 of FIG. 2C.

[0076] Subsequently, a comparatively flat progression of the force/displacement curve G takes place from the position P2 to a position P3 of the mandrels 20, wherein a first irreversible deformation of the contact sleeve 3 takes place in the region P2-P3. The space available for the strand in the contact sleeve 3 is restricted considerably in this region P2-P3 so that a comparatively small void is present in addition to the individual wires 40 of the strand. This state of the contact sleeve 3 and the strand is illustrated in a microsection of the contact sleeve for the region P2-P3 of FIG. 2D.

[0077] In its further progression, the force/displacement curve G assumes a steeper progression again from the position P3 to a position P4 of the mandrels 20, wherein, in addition to an elastic deformation of the strand, a further irreversible deformation of the contact sleeve 3 takes place in the region P3-P4 and the strand occupies almost all of the available space in the contact sleeve 3. This state of the contact sleeve 3 and the strand is illustrated in a microsection of the contact sleeve 3 for the region P3-P4 of FIG. 2E, in which only a few individual wires 40 of the strand are discernable and a void is barely present.

[0078] Subsequently, a comparatively flat progression of the force/displacement curve G again takes place from the position P4 to a position P5 of the mandrels 20, wherein, in addition to a further irreversible deformation of the contact sleeve 3, a non-elastic deformation of the strand also takes place in the region P4-P5. In this region P4-P5, the strand fills the available space in the contact sleeve 3 completely. This state of the contact sleeve 3 and the strand is illustrated in a microsection of the contact sleeve 3 for the region P4-P5 of FIG. 2F, in which individual wires 40 of the strand are not discernible and a void is not present in addition to the strand.

[0079] In this case, FIG. 2F shows a microsection of a crimp with a desirable predefined quality, in which there are no discernable individual wires 40 or splits in the contact sleeve 3 due, for example, to undesired material flaws.

[0080] To this end, FIG. 3C shows the mandrels 20 of the crimping unit 2 in the position P5 of the mandrels 20 which corresponds to the position P5 of the force/displacement curve G, wherein the tips of the mandrels 20 are arranged on a circle with a diameter H, which corresponds to the set crimp height H.

[0081] The force F of the force/displacement curve G of FIG. 2A increases suddenly in this position P5 and reaches its maximum and then decreases when a strain sensor is used. An above force/displacement curve G is suitable for joint display with a reference model M (described below with reference to FIGS. 4A and 4B) in the inventive method V described at the outset and for checking whether the force/displacement curve G is within a tolerance range T of the reference model M, which is delimited by two envelopes GH.

[0082] FIG. 4A shows further force/displacement curves G, G3 and G4 of a crimp together with two envelopes GH of a reference model M according to an embodiment of the invention, and FIG. 4B shows the reference model M for checking the quality of a crimp of FIG. 4A without the force/displacement curves G, G3 and G4.

[0083] The two envelopes GH are each illustrated by dot and dash lines in FIG. 4A and delimit a tolerance range T of a family of reference curves G having a predefined distribution. In this case, the tolerance range T varies over the progression of the envelopes GH and, by way of example and in the position P1 in which the mandrels 20 of a crimping unit 2 are just touching a contact sleeve 3, is narrower than in the position P2 in which an irreversible deformation of the contact sleeve 3 occurs.

[0084] The force/displacement curve G of FIG. 4A is illustrated by a continuous line and is located between the envelopes GH over its entire progression from the position P0 to the position P5 of the mandrels 20, and corresponds to a crimp of a contact sleeve 3 with a cable 4 with a predefined desirable quality.

[0085] The force/displacement curve G3 of FIG. 4A is illustrated by a dashed line and proceeds virtually completely above the two envelopes GH. The force/displacement curve G3 corresponds to a crimp of too large a contact sleeve 3, which is touched and elastically deformed by the mandrels 20 of a crimping unit 2 well before the position P1 provided for touching the contact sleeve 3. Consequently, the force progression F of the force/displacement curve G3 up to the position P2 is well above the tolerance range T.

[0086] For a crimp with a force/displacement curve G3, in addition to the curves G3 and GH, the information that the crimp has an undesired quality owing to an incorrectly large contact sleeve 3 can also be displayed on a screen 50 of a crimping device 1. Moreover, the probability of an above-mentioned fault being present can be calculated from the progression of the force/displacement curve G3 by means of an inventive method V described at the outset and likewise displayed on the screen 50.

[0087] The force/displacement curve G4 of FIG. 4A is likewise illustrated by a dashed line and initially proceeds within the tolerance range T specified by the two envelopes GH. Unlike the force/displacement curve G3, the force/displacement curve G4 corresponds to a crimp of a correct contact sleeve 3 and too small a cable 4 with too small a strand and/or with too few individual wires 40. Owing to the too small a strand or the too few individual wires 40, the force progression F from approximately the position P3 of the mandrels 20 which is described below with reference to FIG. 2A is below a correct force progression F and outside the tolerance range T specified by the two envelopes GH.

[0088] For a crimp with a force/displacement curve G4, in addition to the curves G4 and GH, the information that the crimp has an undesired quality owing to an incorrectly small cable 4 whereof the strand has too few individual wires 40 can be displayed on a screen 50 of a crimping device 1. Moreover, the probability of an above-mentioned fault being present can be calculated from the progression of the force/displacement curve G4 by means of a method V described at the outset and likewise displayed on the screen 50.

[0089] As stated above with reference to FIG. 2A, a reference model M of FIG. 4B is suitable for use in the method V described at the outset for joint presentation and/or for automated comparison with a force/displacement curve of a crimp to be checked.

[0090] FIG. 5 shows a schematic flow chart of a method VM for creating a reference model M of FIG. 4B of a crimp of a predefined cable 4 with a predefined contact sleeve 3 and with a predefined crimp height H using a crimping device 1 of FIG. 1A with the above-described sensor system 13, 14 and the electronic evaluation system 5, wherein a force/displacement curve G, G3, G4 is detected during crimping and displayed on a screen 50. The method VM has, in particular, the following steps S1 to S6.

[0091] In a first step S1, crimping is performed and a force/displacement curve G, G3, G4 of the crimp is detected and displayed on the screen 50.

[0092] In a second step S2, an assessment of the quality of the crimp is performed via visual inspection by an operator and/or with the use of suitable testing instruments. For example, the assessment can be performed optically, in particular by examining a microsection according to FIG. 2F, for example, of a cross-section through the crimp.

[0093] In a third step S3, a force/displacement curve G of a positively assessed crimp with a predefined quality is used for a family of force/displacement curves G with a predefined number n of force/displacement curves G.

[0094] In a fourth step S4, the above first, second and third step is repeated with a further cable 4 and with a further contact sleeve 3, until the predefined number n is reached.

[0095] In a fifth step S5, a tolerance range T with a predefined tolerance and/or taking into account the predefined quality and/or the predefined cable 4 and/or the predefined contact sleeve 3 and/or a predefined crimp height H and/or the predefined number n is defined by specifying a first and second envelope GH which delimit the family of force/displacement curves G.

[0096] In a sixth step S6, the first and second envelope GH and/or the tolerance range T and/or the family of n force/displacement curves G is recorded as a reference model M according to FIG. 4B for use in the inventive method V described at the outset.

[0097] In the sixth step S6, further data characterizing the reference model M and/or a crimp can be stored together with the reference model M, wherein the data can comprise a time stamp and/or a location and/or ID information relating to the crimping device used and/or ID information relating to the operator and/or the predefined number n and/or the predefined cable 4 and/or the predefined contact sleeve 3 and/or the predefined crimp height H and/or information relating to the assessment of force/displacement curves G3, G4 of faulty crimps.

[0098] A performance of the method VM at least from step S1 to step S4 can furthermore be added to a number N of performances of the method VM which have already taken place. In step 5, the tolerance range T can moreover be defined, in particular taking into account the number N and/or the further recorded data characterizing the reference model M and/or a crimp.

[0099] The method VM described above with reference to FIG. 5 can be provided by means of a software program which can be provided on the electronic evaluation system and which is designed in such a way that it can also be used for the method V described at the outset. In this case, the method V and VM can share a plurality of routines of the software program. In this case, an operating mode of the software program which is suitable for the method V and/or VM in each case can be suitably selected by an operator.

[0100] A method V described at the outset can be particularly advantageously used for updating and desirable individual fine-tuning and/or optimization of a reference model M. In this case, a force/displacement curve G of a crimp with a desirable predefined quality can be used for updating the reference model M and step S5 and/or S6 of the method VM can be performed, and/or the performance of a crimping process by means of the method V can be added to the predefined number n and/or the number N. In this case, the update can be performed in an automated manner and/or at the instigation of an operator, wherein, for example, an operating mode of a software program which is suitable for the method V can be switched to an operating mode suitable for the method VM. An advantageously dynamic reference model M and/or dynamic envelopes GH can thus be provided.

[0101] Even where combinations of different aspects or features of the invention are shown in the figures in each case, it is clear to a person skilled in the art—unless indicated otherwise—that the combinations shown and discussed are not the only possible combinations. In particular, mutually corresponding units or feature complexes from different exemplary embodiments can be interchanged with one another.

[0102] Method and device for checking the quality of a crimping

LIST OF REFERENCE SIGNS

[0103] 1 Crimping device [0104] 10 Cylinder [0105] 11 Piston [0106] 12 Adjustment mechanism [0107] 13 Displacement sensor [0108] 130 Lever [0109] 14 Force sensor [0110] 2 Crimping unit [0111] 20 Mandrel [0112] 3 Contact sleeve [0113] 4 Cable [0114] 40 Individual wire [0115] 5 Electronic evaluation system [0116] 50 Screen [0117] F Force [0118] X Displacement [0119] H Crimp height [0120] T Tolerance range [0121] V, VM Method [0122] M Reference model [0123] N, n Number [0124] G, GH, G3, G4 Curve [0125] P0, P1, P2, P3, P4, P5, P6 Position [0126] S1, S2, S3, S4, S5, S6 Step